Telephone system.



MTBE@ No. 969,06?.YN

Jinxnhw N W, W. DEAN.

TELEPUNE SYSTEM. Hummm; rum; Fm, 1e. was.'

C??? i 4%. 0 ff UNITED STATES PATENT OFFICE.

WILLIAM W. DEAN, .OF CHICAGO, ILLINOIS, ASSIGNOR TO' KELLOGG SWITCHBOARD AND.'

SUPPLY COMPANY, OF CHICAGO,

ILLINOIS, A lCORPORATION OF ILLINOIS.

TELEPHOT SYSTEM.

Specification of Letters Patent.

To all whom it may concern; ,-E

`Be it known that I, f WILnrn W. DEAN, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, 'have invented new and use-V following is a'speciicationful Improvements i.n Telephone Systems, of which the My invention relates toV telephone systems and pari ticularly for means associated with lines of the two-2 Wire type by which the Subscribers located vthereon are automatically called .upon the connection being es? tablished at the central oIce.

It is desirable in telephone exchange systemsA to avoid the necessityof manually operating theringing key to call the wanted subscribers. I .therefore arl' range mechanism automatically actuated so `that upon the insertion of the .connecting plug in the jack of the wanted subscriber, the ringing generator is automatic; the line 'and rings thesubscriber .without furtheract uponthe part o the operator. 'i

The apparatus is furtlr'fx arranged upon the response of the called subscribeitfto automatically disconnect' thel ringing generator. h

In `the accompanying drawing in which the sameref? erence characters indicate like parts throughout the several, views, -Figure lis'a diagram` of ateleph/one systern embodying my improvements V; Fig. kZie a diagram of a slightly modified arrangement; Fig.' 3 i`s a second modification, andf Fig. 4 is adiagrafn of a different arrangement.' f

Referring to Fig. l7 L and L2 indicate two subscribers lines extending in two limbs 2 and-S'from .the respecti've substations to the central oflice. At the substation A a transmitter 4- and receiver 5 are adapted to be included in a bridge of the linp Vbya switchhopk 6 when the, receiver is removedY therefrom, and a condenser 7 and call b ell 8 are permanently connected inv a'bridge of the line. Thr-same apparatus exists at the station B `and at all the ther stations of lthe system.

.Any other suitable substation-outfit may be provided in' place otthat shown.'

At the central officetlre'lines are tted with a callv ing signal'Smi'itlian answering jack J together' with multiple jacks J2, J3 in any'nuinber. A cut-off relay R is provided for each line, the winding of which is legged to ground from the sleeve conductor of the jacks. The springs of the cut-off relay serve to' normally con- .nect the line conductor Zwiththe grounded branch 9- V and the sleeve 'conductor 3 with the conductor 1U lead'- ing to thefline relay R2 which controls the circuit of the line signal S and the other sideofrwhichris con nected by meansof a conduetorll with the live pole;

of a central-and common.sou'rcemo-i` current B. The forward contacts foflthe springs of said clitoff relay R serve toj'oin the switchboard section 'of the line With` A the external line circuit duringconversation.

.The rc )perators outtvcomprises a cordcircuit having an answering plug P and a calling plug P2 providedwith tip and sleeve Contact surfaces adapted to Patented oct. 22, 190'?. l

register with the corresponding surfaces of the spring the interposed .condenser c2. The battery B is bridged 65 across the answering end `of the cord circuit and includes upon either side the supervisory relays r and r2, the former ,controlling through vits normally closedl contacts and the latter through its normally open'contacts the local circuit of supervisory signal S2, which is .E

' associated with the answering plug P. lA similar bat- Zcircuit and includes upon either side the supervisory `"relays r3 and r. .whichcontrol in a manner similar to the'other pair olifA supervisory relays a local circuit of supervisory lamp S3 which is associated with the 'call-A ing plug P2. Sleeve 'supervisory'relay This provided with an additional spring v1-2 serving normally: to connect through "conductorlSv with atertiary'winding14 of the opera- Y,

tor-s induction coil, or with other testreceptive device. The 4forward `conta'ctof said spring-12 isconnected means of conductor '15 with a spring 16 of a ringing re.`

lay which has its main actuating winding 17 con/f contact of its said spring land upon the other side nectedupon one side by conductor 18 the normal v with the ringing generator 19. The forward'contact of said spring 16 is connected with the middle portion othetip strand t2 of the cord circuit. A locking windnfgvZQ isprovided upon the ringing relay iwhieh' is connected with spring 21 thereof while' the forward Contact of said spring is joined by conductor 22 to the point 23 located upon the local v lamp S3.

The battery B2 preferablyserves many lines and is connected therewith by means of a branch 11;

In the operation of the system the subscriber A takes up his receiver and completes apath for current ovei` his-line circuit from the central battery B. Theline-relay R2 actuates and closes the local circuit of the circuit of supervisory- .70 'i tery B2 bridged' across the calling end of the cord f signal S. Upon observing this signal the operator insorts the plug P-of her cordl circuit in the answering jack'of the calling subscriber and connects her telephone in circuit to receivethe order. The insertion of the plug P first closes a local circuit from the battery 1 3 through the supervisory relay 12, over `thesleeve 1054 strand s of the cord circuit, the 'sleeve conductor of the jacksand thence through the winding of the cutoff relaylR. Both relays respond to this current,I the 'gut-off relay servingv to sever the normal connections `ot' thefline conductor and to connect the jacks with the 11C 3G cut-oft relay oi the line.

line, while the supervisory relay TA2 serves to closeth'e and prevents the lighting ei lamp S2. Upon learningA the order the operator tests the condition of the wanted line by touching the tip oi her Ialling plug I to the i test ring oi the jack before her oi the line wanted. In

case the line is idle it is evident that the testy rings are connected w'th ground through the cutoff relay of the line and since the tip oi the plug is likewise connected with ground through the tertiary winding 'li vl ofthe operator-s induction coil the said tip and test contacts are at the same potential and consequently no click i` received. 1n case the line is busy the said test rings are connected with the live pole of the batteryli or i313, through the sleeve strand of the inserted 2G plug, so that when the grounded tip of the testing plug is touched to the said test rings a flow of current results and a click is received. The high resistance and impedance ofthe tertiary winding 14 serves to prevent too great or'sudden a v iation oi current upon the connected lines so that they are not disturbed by noise in their instruments. Upon tinding a line idle the calling plug P2 is inserted in the jack ot the line which results in energizing the sleeve supervisory relay 1" over the sleeve conductors and through the The actuation of the latter serves to connect the two portions ot the line together and to render the signals of the line inoperative, while th:1 former completes the local circuit ot the superyisory lamp S3 which is lighted and disconnects through S5 its spring 12 the said tertiary winding and engages with the conductor l5 leading to the ringing relay 1"". 'lhis now connects the ringing generator in circuit. which causes current to tiow from generator through .the winding 17 oi said relay T5. conductor 1S, spring lt.

#i0 conductor 1.3, spring 12y the forward portion of tip strand t?, the tip side of the line, through the condenser and bell at the substation and thence back to the central otiice over the sleeve conductor ot' the line, the sleeve strand s` oi the cord circuit and through the l supervisory relay TA1 and talking battery ll'J to ground.

This path is oi sutiicient resistance to prevent the ac tti-ation oi relay T5 but the current flow is enough to actuate the callvbell b at the' subscriber-s station. flipon the response oi the called subscriber a path for lower res stance is provided at the substation which permits a sutlicient increase in the ringing current to energY ze said ri iging relay T5 which serves in the first instance to disconnect the genera. n 19 through its spring .iti and to complete the tip strand l? of the cord circuit. through the forward contact ot said spring which places the said cord circuit strand in condition or conversation. and secondly a locking circuit is esA tabiishedV ier said relay through its winding 2() by means ot' conductor 22 and spring 2l. 'lhe ringing erator being now disconnected and the metallic circuit completed current from the battery lll) flows thereover and actu-stes tip supervisory relay T3, thus oth-ning t-.unp Sv the circuit oi and extinguishing supervisory llay r7.

to indicate to the operator that the called sub i 513 scriber has responded and the parties are in communication. Should the lamp S3 remain lightedl for some time the operator will understand tliatthe call/gl subscriber has not responded and she, will take down the connection. At the termination of the cox-.ersation the subscribers return their receivers to the hooks, thus cutting off current from the metallic lines and denergizing tip supervisory relays T and T3. This lights the two supervisory lamps associated with the cord circuit., upon observing which the operator takes down the connection and restores all parts to normal condition. 1t will be observed that. aiter the ringing relay is once locked it cannot be again energized until the withdrawal of the connecting plug.

Fig. 2 shows a modified arrangement in which the tip strand is normally completed through a key 25 and is thence connected by spring l2 ot relay T4 with a high resistance and high impedance test relay T" and serves when said relay is energized to complete through its spring 12, the tip strand t2 of the cord circuit. The sleeve relay T4 is in series with a relay T7 in the branch leading from the battery B2 to the sleeve strand si' ot" the cord circuit. A shunt oi said latter relayisvcontrolled through the normally open contacts of the ringing relay T'". 1n testing a wanted line in this arrangement. the testing circuit may flow over the tip strand and through the high resistance and high impedance test relay T'". 'Ihe insertion of the plug of thc cord circuit actuales sleeve relay r" to close a local circuit of supervisory-sig. nal S and at the same time disconnects the test relay and places the tip strand in condition tor talking. 'lhe relay ri is likewise vitalized but the arrangement is such that the key 25 carrying an armature for said relay is out of the operating ield of i'orce of said relay so that the said key is not attracted. ln order to connect the generator in circuit, the operator depresses the key 25 which engages contact 2o and est ablishcs a path ior the ringing current from the generator lt). The relay T7 serves now to hold said spring depressed. 'lhe high re' sistance ringing path prevents the actuation oi relay r until the called subscriber responds7 when the low resistance path permits a sutlicient increase ot' the ringing current though alternating in character to actuate said relay and cause it -to close the shunt about re- 'lhe latter relay being deprived tit' current permits the return-oi key 25 to normal position which disconnects the generator and places the tip strand in condition for talking. Ordinarily the supervisory relays should have about 100 ohms resistance in which case the relays TM1 and r7 should each have 5() ohms resistance.

111 Fig. 3 the relay r7 is also connected in series with the sleeve relay T4 and each may have 5t) olnns resistance, 'lhe forward portion oi the tip strand t`- ot the cord circuit connected to spring ltloi the relay T7 which is normally connected to the high resistance and high impedance test. relay r". Upon the insertion of the connecting plug P2 the relay T7 is energized and attracts the armature carrying the said spring 30. This spring in its movement disconnects the test relay and then engages with the end oi the armature of the ringing relay T`rl and is thereby held, while the further attraction of said relay 1'7 brings the spring 3l suitably connected with spring 3() into engagement with said spring 30, thereby connecting the ringing generator 19 in circuit.. This is subscriber. The tip strand being still open at contact have 500 ohms resistance provided in connection with relay T7, but thelatter is' placed in parallel with the sleeve supervisory relay l and the ringing relay r5 is -arranged to open the circuit thereof upon the response of the called subscriber. The operation will be readily understood. vRelay T7 may. while relayr Vhas the usual 100ohms. v". l

.Although I 'have described several modifications oi l vmy invention, it will be apparent that various alterations may be made therein and still be withinlthe scope and principle ofl'ny invention.

Other types of line circuits in which the cut-ofi' relays are actuated over portions of the talking circuits i may obviously be employed andstill be within the scope Aof my invention. v l

Any usual'type' of listening keynla'y be employed.

I claimzv '1. In a telephone system, thecolnbination with a telephone line, of a Vsignal therefor, a relay actuated over a,` portion of the talking circuit when a connection is established with tlle'line to render said signal inoperativea rlnglngjgenerator, means for connectingr said generator in circuit to call the wanted subscriber, and means auto-- inutically controlled by the subscriber in his response to vthe cali for disconnecting said generator at the central "oiiice, 'substantially as described. l

2. In a telephone system, the combination witil a piurality of telephone lines euch ilavilu,r a cutoff relay actuated over a portion of the talking circu-it, a ringing generator adapted to be connected with a line to call n walted subscriber, means lior maintaining.;r said cut-oit relay actuated during,r ringing, and automatic' means controlled by the called subscriber for disconnectingv said generator at `the central otlice, substantially as described.

3. in a.telephonesysteln, the combination with a plurality of subscribers' lines, of signals fol' said lines, cutoii' relays therefor adapted to render the signals inoperative during a connection, said relay circuits including,r portions of the talking circuits,` a ringing generator adapted to be connected with the lilies to cali tile wanted subscribers, means for-maintaining the cut-oli relays actuated during ringing, and automatic llleans controlled by the called subscribers in their response to th .ils to sever the connection of the generator at the centraloliice, substantiaily as described. l

4. In a telephone system, the combination with telephone lines having lille signals, of a cut-olf relay for each line adapted to be actuated bycurrent ever a portionot `inoperative when connections over portions of the talking circuit, ot a source ol ring-,'-

the talking circuit to render the line signal for the line inoperative, a ringing generator, means to automatically v connect said generator with the called line by the act of establishing n connection therewith, means lll.-lintail\ing the cutfoit' relay actuated during ringing, and means lo disconnectsaid generator automatically upon the response of the called subscriber, substantially as described.

5. In a telephone system, tile combination with telephone lines having line signz1i\s',.said `signals llcinf.,r rendered inoperative when connections ale established by current over portions 'of the talking; circuit, of a source of ringing current adapted to be connected `witll the lines to call the wanted subscribers, and lne-.ins toautomaticaily disconnect the said source after the subscribers h'arc been called. substantially asldescribed. i

6. In a telephone system, the combination with telephone lines having,l line signals said signals bein;l rendered 'e established by currenting current adapted to be'automaticaily connected with the called lilies when a connection is established therewith, and means under the control of the subscriber for automatically disconnecting said source, substantially as described.

7.4111 a. telephone system, the combination with telephone lines having',r line signals, said signals beingrendered cord circuit and actuated over a local circuit including a p local circuit including a portion of the talking circuit when the cord circuit is connected for use, a. source of ringing current, and means depending upon the actuation of said relay for connecting' said ringing source with a strand oi the cord circuit, and further means actuated upon the response of the called sub iller for again disconnectingsaid source from said cord circuit strand. substantially as described.

l,ned by lne at Chicago, county of Cook, VSlate oi' Illinois,` this 0th day of l `ebrualy 1903.

llllillAM W. DEAN.

Witnesses 1 irloln'zlrr Lllwls Anas, Gllzlslmn Broun. 

